994 research outputs found
An economically viable ionic liquid for the fractionation of lignocellulosic biomass
Cost-effective fractionation (pretreatment) of lignocellulosic biomass is necessary to enable its large-scale use as a source of liquid fuels, bio-based materials and bio-derived chemicals. While a number of ionic liquids (ILs) have proven capable of highly effective pretreatment, their high cost presents a barrier to commercial viability. In this study, we investigate in detail the application of the low-cost (ca. $1 kg−1) ionic liquid triethylammonium hydrogen sulfate for the fractionation of the grass Miscanthus x giganteus into a cellulose rich pulp, a lignin and a distillate. We found that up to 85% of the lignin and up to 100% of the hemicellulose were solubilized into the IL solution. The hemicellulose dissolved mainly in monomeric form, and pentoses were partially converted into furfural. Up to 77% of the glucose contained in the biomass could be released by enzymatic saccharification of the pulp. The IL was successfully recovered and reused four times. A 99% IL recovery was achieved each time. Effective lignin removal and high saccharification yields were maintained during recycling, representing the first demonstration that repeated IL use is feasible due to the self-cleaning properties of the non-distillable solvent. We further demonstrate that furfural and acetic acid can be separated quantitatively from the non-volatile IL by simple distillation, providing an easily recoverable, valuable co-product stream, while IL degradation products were not detected. We further include detailed mass balances for glucose, hemicellulose and lignin, and a preliminary techno-economic estimate for the fractionation process. This is the first demonstration of an efficient and repeated lignocellulose fractionation with a truly low-cost IL, and opens a path to an economically viable IL-based pretreatment process
Disruption of Kcc2-dependent inhibition of olfactory bulb output neurons suggests its importance in odour discrimination
Synaptic inhibition in the olfactory bulb (OB), the first relay station of
olfactory information, is believed to be important for odour discrimination.
We interfered with GABAergic inhibition of mitral and tufted cells (M/T
cells), the principal neurons of the OB, by disrupting their potassium-
chloride cotransporter 2 (Kcc2). Roughly, 70% of mice died around 3 weeks, but
surviving mice appeared normal. In these mice, the resulting increase in the
intracellular Cl− concentration nearly abolished GABA-induced
hyperpolarization of mitral cells (MCs) and unexpectedly increased the number
of perisomatic synapses on MCs. In vivo analysis of odorant-induced OB
electrical activity revealed increased M/T cell firing rate, altered phasing
of action potentials in the breath cycle and disrupted separation of odour-
induced M/T cell activity patterns. Mice also demonstrated a severely impaired
ability to discriminate chemically similar odorants or odorant mixtures. Our
work suggests that precisely tuned GABAergic inhibition onto M/T cells is
crucial for M/T cell spike pattern separation needed to distinguish closely
similar odours
S6K1 and 4E-BP1 Are Independent Regulated and Control Cellular Growth in Bladder Cancer
Aberrant activation and mutation status of proteins in the phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) and the mitogen activated protein kinase (MAPK) signaling pathways have been linked to tumorigenesis in various tumors including urothelial carcinoma (UC). However, anti-tumor therapy with small molecule inhibitors against mTOR turned out to be less successful than expected. We characterized the molecular mechanism of this pathway in urothelial carcinoma by interfering with different molecular components using small chemical inhibitors and siRNA technology and analyzed effects on the molecular activation status, cell growth, proliferation and apoptosis. In a majority of tested cell lines constitutive activation of the PI3K was observed. Manipulation of mTOR or Akt expression or activity only regulated phosphorylation of S6K1 but not 4E-BP1. Instead, we provide evidence for an alternative mTOR independent but PI3K dependent regulation of 4E-BP1. Only the simultaneous inhibition of both S6K1 and 4E-BP1 suppressed cell growth efficiently. Crosstalk between PI3K and the MAPK signaling pathway is mediated via PI3K and indirect by S6K1 activity. Inhibition of MEK1/2 results in activation of Akt but not mTOR/S6K1 or 4E-BP1. Our data suggest that 4E-BP1 is a potential new target molecule and stratification marker for anti cancer therapy in UC and support the consideration of a multi-targeting approach against PI3K, mTORC1/2 and MAPK
Rapid divergence and expansion of the X chromosome in papaya
X chromosomes have long been thought to conserve the structure and gene content of the ancestral autosome from which the sex chromosomes evolved. We compared the recently evolved papaya sex chromosomes with a homologous autosome of a close relative, the monoecious Vasconcellea monoica, to infer changes since recombination stopped between the papaya sex chromosomes. We sequenced 12 V. monoica bacterial artificial chromosomes, 11 corresponding to the papaya X-specific region, and 1 to a papaya autosomal region. The combined V. monoica X-orthologous sequences are much shorter (1.10 Mb) than the corresponding papaya region (2.56 Mb). Given that the V. monoica genome is 41% larger than that of papaya, this finding suggests considerable expansion of the papaya X; expansion is supported by a higher repetitive sequence content of the X compared with the papaya autosomal sequence. The alignable regions include 27 transcript-encoding sequences, only 6 of which are functional X/V. monoica gene pairs. Sequence divergence from the V. monoica orthologs is almost identical for papaya X and Y alleles; the Carica-Vasconcellea split therefore occurred before the papaya sex chromosomes stopped recombining, making V. monoica a suitable outgroup for inferring changes in papaya sex chromosomes. The papaya X and the hermaphrodite-specific region of the Y(h) chromosome and V. monoica have all gained and lost genes, including a surprising amount of changes in the X
Sodium butyrate and tributyrin induce in vivo growth inhibition and apoptosis in human prostate cancer
Brown dwarf census with the Dark Energy Survey year 3 data and the thin disc scale height of early L types
27 pages, 18 figuresIn this paper we present a catalogue of 11 745 brown dwarfs with spectral types ranging from L0 to T9, photometrically classified using data from the Dark Energy Survey (DES) year 3 release matched to the Vista Hemisphere Survey (VHS) DR3 and Wide-field Infrared Survey Explorer (WISE) data, covering ≈2400 deg2 up to iAB = 22. The classification method follows the same phototype method previously applied to SDSS-UKIDSS-WISE data. The most significant difference comes from the use of DES data instead of SDSS, which allow us to classify almost an order of magnitude more brown dwarfs than any previous search and reaching distances beyond 400 pc for the earliest types. Next, we also present and validate the GalmodBD simulation, which produces brown dwarf number counts as a function of structural parameters with realistic photometric properties of a given survey. We use this simulation to estimate the completeness and purity of our photometric LT catalogue down to iAB = 22, as well as to compare to the observed number of LT types. We put constraints on the thin disc scale height for the early L (L0–L3) population to be around 450 pc, in agreement with previous findings. For completeness, we also publish in a separate table a catalogue of 20 863 M dwarfs that passed our colour cut with spectral types greater than M6. Both the LT and the late M catalogues are found at DES release page https://des.ncsa.illinois.edu/releases/other/y3-mlt.Peer reviewedFinal Published versio
Transfer learning for galaxy morphology from one survey to another
© 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.Deep Learning (DL) algorithms for morphological classification of galaxies have proven very successful, mimicking (or even improving) visual classifications. However, these algorithms rely on large training samples of labelled galaxies (typically thousands of them). A key question for using DL classifications in future Big Data surveys is how much of the knowledge acquired from an existing survey can be exported to a new dataset, i.e. if the features learned by the machines are meaningful for different data. We test the performance of DL models, trained with Sloan Digital Sky Survey (SDSS) data, on Dark Energy survey (DES) using images for a sample of 5000 galaxies with a similar redshift distribution to SDSS. Applying the models directly to DES data provides a reasonable global accuracy ( 90%), but small completeness and purity values. A fast domain adaptation step, consisting in a further training with a small DES sample of galaxies (500-300), is enough for obtaining an accuracy > 95% and a significant improvement in the completeness and purity values. This demonstrates that, once trained with a particular dataset, machines can quickly adapt to new instrument characteristics (e.g., PSF, seeing, depth), reducing by almost one order of magnitude the necessary training sample for morphological classification. Redshift evolution effects or significant depth differences are not taken into account in this study.Peer reviewedFinal Accepted Versio
Categorical versus continuous circulating tumor cell enumeration as early surrogate marker for therapy response and prognosis during docetaxel therapy in metastatic prostate cancer patients
Background: Circulating tumor cell (CTCs) counts might serve as early surrogate marker for treatment efficacy in metastatic castration-resistant prostate cancer (mCRPC) patients. We prospectively assessed categorical and continuous CTC-counts for their utility in early prediction of radiographic response, progression-free (PFS) and overall survival (OS) in mCRPC patients treated with docetaxel. Methods: CTC-counts were assessed in 122 serial samples, as continuous or categorical (= 5 CTCs) variables, at baseline (q0) and after 1 (q1),4 (q4) and 10 (q10) cycles of docetaxel (3-weekly, 75 mg/m2) in 33 mCRPC patients. Treatment response (TR) was defined as non-progressive (non-PD) and progressive disease (PD),by morphologic RECIST or clinical criteria at q4 and q10. Binary logistic and Cox proportional hazards regression analyses were used as statistical methods. Results: Categorical CTC-count status predicted PD at q4 already after one cycle (q1) and after 4 cycles (q4) of chemotherapy with an odds ratio (OR) of 14.9 (p = 0.02) and 18.0 (p = 0.01). Continuous CTC-values predicted PD only at q4 (OR 1.04, p = 0.048). Regarding PFS, categorical CTC-counts at q1 were independent prognostic markers with a hazard ratio (HR) of 3.85 (95 % CI 1.1-13.8, p = 0.04) whereas early continuous CTC-values at q1 failed significance (HR 1.02, 95 % CI 0.99-1.05, p = 0.14). For OS early categorical and continuous CTC-counts were independent prognostic markers at q1 with a HR of 3.0 (95 % CI 1.6-15.7, p = 0.007) and 1.02 (95 % CI 1.0-1.040, p = 0.04). Conclusions: Categorical CTC-count status is an early independent predictor for TR, PFS and OS only 3 weeks following treatment initiation with docetaxel whereas continuous CTC-counts were an inconsistent surrogate marker in mCRPC patients. For clinical practice, categorical CTC-counts may provide complementary information towards individualized treatment strategies with early prediction of treatment efficacy and optimized sequential treatment
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H0LiCOW X: Spectroscopic/imaging survey and galaxy-group identification around the strong gravitational lens system WFI2033-4723
Galaxies and galaxy groups located along the line of sight towards
gravitationally lensed quasars produce high-order perturbations of the
gravitational potential at the lens position. When these perturbation are too
large, they can induce a systematic error on of a few-percent if the lens
system is used for cosmological inference and the perturbers are not explicitly
accounted for in the lens model. In this work, we present a detailed
characterization of the environment of the lens system WFI2033-4723 (, = 0.6575), one of the core targets of the H0LICOW
project for which we present cosmological inferences in a companion paper (Rusu
et al. 2019). We use the Gemini and ESO-Very Large telescopes to measure the
spectroscopic redshifts of the brightest galaxies towards the lens, and use the
ESO-MUSE integral field spectrograph to measure the velocity-dispersion of the
lens ( km/s) and of several nearby
galaxies. In addition, we measure photometric redshifts and stellar masses of
all galaxies down to mag, mainly based on Dark Energy Survey imaging
(DR1). Our new catalog, complemented with literature data, more than doubles
the number of known galaxy spectroscopic redshifts in the direct vicinity of
the lens, expanding to 116 (64) the number of spectroscopic redshifts for
galaxies separated by less than 3 arcmin (2 arcmin) from the lens. Using the
flexion-shift as a measure of the amplitude of the gravitational perturbation,
we identify 2 galaxy groups and 3 galaxies that require specific attention in
the lens models. The ESO MUSE data enable us to measure the
velocity-dispersions of three of these galaxies. These results are essential
for the cosmological inference analysis presented in Rusu et al. (2019).Comment: Matches the version accepted for publication by MNRAS. Note that this
paper previously appeared as H0LICOW X
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